Vessel and method for removal and/or installation of at least a part of a sea platform

ABSTRACT

A vessel for removal and/or installation of at least a part of a sea platform includes a support structure and a top side. The vessel includes a hull and two support arms located at a distance from each other and attached to the hull. In use, the support arms extend beyond the hull in a substantially horizontal direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/525,287, filed Aug. 19, 2011, and 61/560,966, filed Nov. 17, 2011,and claims the benefit of Netherlands Application No. 2007282, filedAug. 19, 2011, the contents of all of which are incorporated byreference herein.

FIELD OF THE INVENTION

The invention relates to a vessel for removal and/or installation of atleast a part of a sea platform comprising a support structure and a topside.

SUMMARY OF THE INVENTION

It is an object of the invention to provide an improved or at leastalternative vessel for removing and installing at least a part of a seaplatform comprising a support structure and a top side.

This object is achieved by the vessel according the invention. Saidvessel for removal and/or installation of at least a part of a seaplatform comprising a support structure and a top side comprises a hulland two support arms located at a distance from each other and attachedto the hull, wherein the support arms in use extend beyond the hull in asubstantially horizontal direction. The support structure may forexample comprise a frame work or one or more support legs. The top sidemay for example comprise equipment for exploitation of oil and/or gasfrom the seabed or a wind turbine for producing electricity.

In an embodiment of the vessel according the invention, the support armsare constructed and arranged to in use fully support said at least onepart of the sea platform.

In an embodiment of the vessel according the invention, the support armsextend over a distance between 10 and 100 m beyond the hull. The supportarms may extend over a distance of more than 20 m beyond the hull

In an embodiment of the vessel according the invention, the support armsextend along the hull over a distance between 10 and 100% of the lengthof the hull. The support arms may extend along the hull over a distancebetween 25-75% of the length of the hull.

In an embodiment of the vessel according the invention, the distancebetween the support arms is between 10 and 100 m.

In an embodiment of the vessel according the invention, the support armsare located above the water surface when carrying said at least one partof the sea platform. The support arms may extend substantially parallelto each other. The vessel comprises a roll axis and the support arms mayextend substantially parallel to the roll axis.

In an embodiment of the vessel according the invention, the support armsare movable relative to the hull.

In an embodiment of the vessel according the invention, the support armsare movable relative to each other.

In an embodiment of the vessel according the invention, the support armsare movable in a direction transverse to the roll axis.

In an embodiment of the vessel according the invention, the support armsare movable in a direction perpendicular to the roll axis.

In an embodiment of the vessel according the invention, the support armsare movable along a support trajectory.

In an embodiment of the vessel according the invention, the supporttrajectory extends transverse to the roll axis.

In an embodiment of the vessel according the invention, the supporttrajectory extends perpendicular to the roll axis.

In an embodiment of the vessel according the invention, the vesselcomprises a support rail and the support arms are moveable along thesupport rail.

In an embodiment of the vessel according the invention, the support railextends transverse to the roll axis.

In an embodiment of the vessel according the invention, the support railextends perpendicular to the roll axis.

In an embodiment of the vessel according the invention, the support raildefines the support trajectory.

In an embodiment of the vessel according the invention, the vesselcomprises an arm driving system constructed and arranged to move thesupport arms relative to the hull.

In an embodiment of the vessel according the invention, the arm drivingsystem moves the support arms along the support trajectory.

In an embodiment of the vessel according the invention, the arm drivingsystem moves the support arms along the support rails.

In an embodiment of the vessel according the invention, the vesselcomprises an arm fixating system constructed and arranged to fixate thesupport arms relative to the hull.

In an embodiment of the vessel according the invention, the support armsare movable from a distance of 10 m between the support arms to adistance of 100 m between the support arms, and vice versa.

In an embodiment of the vessel according the invention, the vesselcomprises at least one docking unit.

In an embodiment of the vessel according the invention, at least onedocking unit is attached to the support arms.

In an embodiment of the vessel according the invention, at least onedocking unit is attached to the inner arm surfaces of the support arms.

In an embodiment of the vessel according the invention, at least onedocking unit is attached to the hull.

In an embodiment of the vessel according the invention, at least onedocking unit is attached to the first hull side.

The vessel according the invention may comprise any feature orcombination of features as defined in the clauses.

The invention further relates to a method for removing at least a partof a sea platform comprising a support structure and a top side, whichmethod comprises;

-   providing a vessel according to the invention,-   positioning the support arms under the top side such that the    support structure is located between the support arms,-   raising the support arms relative to the water surface to fully    support the top side with the support arms,-   continuing the raising of the support arms to move the top side at a    distance from the support structure, and-   moving the vessel away from the support structure in a substantially    horizontal direction while fully supporting the top side with the    support arms.

The invention further relates to a method for removing at least part ofa sea platform comprising a support structure and a top side, whichmethod comprises;

-   providing a vessel according to the invention,-   connecting the hoisting system to the support structure, and-   raising the support structure with the hoisting system in a    substantially vertical direction while fully supporting the support    structure with the support arms.

The invention further relates to a method for installing at least a partof a sea platform comprising a support structure and a top side, whichmethod comprises;

-   providing a vessel according to the invention, wherein the top side    of the sea platform is fully supported by the support arms,-   positioning the top side above the support structure such that the    support structure is located between the support arms,-   lowering the support arms relative to the water surface to place the    top side on the support structure,-   continuing the lowering of the support arms to fully transfer the    weight of the top side to the support structure and to move the    support arms at a distance from the top side and-   moving the vessel away from the support structure in a substantially    horizontal direction.

The invention further relates to a method for installing at least a partof a sea platform comprising a support structure and top side, whichmethod comprises;

-   providing a vessel according to the invention, wherein the support    structure is connected to the hoisting system and fully supported by    the support arms,-   lowering the support structure with the hoisting system in a    substantially vertical direction such that the support structure is    placed on the seabed or a foundation provided on the seabed, and-   disconnecting the hoisting system from the support structure.

In an embodiment of the method according the invention, the methodcomprises moving the support arms relative to the hull.

In an embodiment of the method according the invention, the methodcomprises moving the support arms relative to each other.

In an embodiment of the method according the invention, the methodcomprises moving the support arms towards each other.

In an embodiment of the method according the invention, the methodcomprises moving the support arms away from each other.

In an embodiment of the method according the invention, the methodcomprises moving the support arms in a direction transverse to the rollaxis.

In an embodiment of the method according the invention, the methodcomprises moving the support arms in a direction perpendicular to theroll axis.

In an embodiment of the method according the invention, the methodcomprises moving the support arms along the support trajectory.

In an embodiment of the method according the invention, the methodcomprises moving the support arms along the support rail.

In an embodiment of the method according the invention, the methodcomprises moving the support arms to match the dimensions of the topside which in use will be supported.

In an embodiment of the method according the invention, the methodcomprises moving the support arms to match the dimensions of the supportstructure which in use will be supported.

In an embodiment of the method according the invention, the methodcomprises fixating the support arms relative to the hull in a supportposition.

In an embodiment of the method according the invention, the methodcomprises docking the vessel at the support structure via the at leastone docking unit.

In an embodiment of the method according the invention, the methodcomprises moving the support arms relative to the hull after the dockingof the vessel.

In an embodiment of the method according the invention, the methodcomprises fixating the support arms relative to the hull after thedocking of the vessel.

In an embodiment of the method according the invention, the methodcomprises moving said at least one part supported by the support armsalong said support arms.

In an embodiment of the method according the invention, the methodcomprises moving said at least one part supported by the support armsalong the deck of the vessel.

In an embodiment of the method according the invention, the methodcomprises moving said at least one part supported by the support arms inthe direction of the roll axis of the vessel.

In an embodiment of the method according the invention, the methodcomprises moving said at least one part carried by the hoisting systemalong said support arms with the driving system.

In an embodiment of the method according the invention, the methodcomprises moving said at least one part carried by the hoisting systemalong the rails.

In an embodiment of the method according the invention, the methodcomprises moving the hoist members along the support arms with thedriving system while carrying the said at least one part.

In an embodiment of the method according the invention, the methodcomprises placing said at least one part carried by the hoisting systemon the deck of the vessel.

In an embodiment of the method according the invention, the methodcomprises transferring said at least one part from the vessel onto aquay by positioning the second hull side adjacent to the quay and movingsaid at least one part from the vessel to the quay while moving over thesecond hull side.

In an embodiment of the method according the invention, the methodcomprises transferring said at least one part from a quay onto thevessel by positioning the second hull side adjacent to the quay andmoving said at least one part from the quay to the vessel while movingover the second hull side.

The method according the invention may comprise any feature orcombination of features as defined in the clauses.

BRIEF DESCRIPTION OF THE DRAWINGS:

Embodiments of the vessel and method according the invention will bedescribed by way of example only, with reference to the accompanyingschematic drawings in which corresponding reference symbols indicatecorresponding parts, and in which:

FIG. 1 schematically shows a view in perspective of an embodiment of thevessel,

FIG. 2 schematically shows a side view of the vessel of FIG. 1,

FIG. 3 schematically shows a top view of the vessel of FIG. 1,

FIGS. 4-11 schematically show a further embodiment of the vessel,

FIGS. 12-14 schematically show a further embodiment of the vessel,

FIGS. 15 and 16 schematically show an alternative embodiment of thevessel of the FIG. 12-14,

FIG. 17 schematically shows a view in perspective of a furtherembodiment of the vessel,

FIG. 18 schematically shows a view in perspective of a furtherembodiment of the vessel,

FIGS. 19-22 schematically show a further embodiment of the vessel,

FIGS. 23-26 schematically show a further embodiment of the vessel,

FIG. 27 schematically shows a further embodiment of the vessel, and

FIG. 28 schematically shows a further embodiment of the vessel.

DETAILED DESCRIPTION OF THE INVENTION:

The FIGS. 1-3 show an embodiment of the vessel which is used for removaland/or installation of at least one part of a sea platform 2 comprisinga support structure 4 and a top side 5. The vessel 1 comprises a hull 6and two support arms 11, 12. The support arms 11, 12 are located at adistance from each other and attached to the hull 6. The support arms11, 12 in use extend beyond the hull 6 in a substantially horizontaldirection. The support arm 11, 12 are constructed and arranged to in usefully support said at least one part 4, 5 of the sea platform 2. Arrow26 indicates a horizontal direction and arrow 27 indicates a verticaldirection.

The support arms 11, 12 extend over a distance L2 of around 50 metersbeyond the hull 6. In other examples, the support arms 11, 12 can extendbetween 10 and 100 m beyond the hull 6.

The support arms 11, 12 extend along the hull 6 over a distance L3 ofaround 40% of the length of the hull 6. In an alternative embodiment,the support arms 11, 12 can extend between 10 and 100% of the length ofthe hull 6.

The total length of the support arms 11, 12 is L1. The part of thesupport arms 11, 12 extending beyond the hull 6 forms the outboardextending part 33. The length of the outboard extending part 33 of thesupport arms 11, 12 is L2. The part of the support arms 11, 12 extendingalong the hull 6 forms the inboard extending part 34. The length of theinboard extending part 34 of support arms 11, 12 is length L3.

The support arms 11, 12 comprise an outer arm surface 13, inner armsurface 14, upper arm surface 15 and lower arm surface 16. The distanceD1 between the outer arm surfaces 13 of the support arms 11, 12 isaround 80 meters. In an alternative embodiment, the distance D1 can bebetween 10 and 100 m. The distance D1 may be smaller or equal to 77.5meter. The distance D2 between the inner surfaces 14 of the support arms11, 12 is around 75 meters. In an alternative embodiment, the distanceD1 can be between 10 and 100 m.

The support arms 11, 12 extend substantially parallel to each other. Thesupport arms 11, 12 are located above the water surface when carryingsaid at least one part 4, 5 of the sea platform 2.

The vessel 1 comprises a roll axis 8, a yaw axis 9 and a pitch axis 10.The support arms 11, 12 extend substantially parallel to the roll axis9.

The support arms 11, 12 comprise a first arm end 17 located outboard anda second arm end 18 located inboard. The vessel 1 comprises a deck 20.An inclined surface 28 is located at the second arm end 18 of thesupport arms 11, 12. The inclined surface 28 extends from the upper armsurface 15 to the deck 20.

The hull 6 comprises a first hull side 21, a second hull side 22, athird hull side 23 and a fourth hull side 24. The support arms 11, 12extend from the first hull side 21.

Support units 52 are attached to the support arms 11, 12. The supportunits 52 are coupled to rails 51 provided on the support arms 11, 12.Additional support units 52 can be attached to the hull 6. The supportunits 52 comprise a support surface 19 on which said at least one part4, 5 of the sea platform 2 is placed. This means that the support units52 form the support surface 19 on which said at least one part 4, 5 ofthe sea platform 2 is placed when carried by the support arms 11, 12.The support units 52 are movable along the rails 51. This allows thatthe support units 52 are moved in positions that suit the part to besupported. The support units 52 are actively movable. This way a drivingsystem 31 constructed and arranged to in use move said at least one part4, 5 along the support arms 11, 12 is provided. The support units 52 aremoveable in the direction of the roll axis 8. In alternativeembodiments, the support units 52 are attached to the support arms 11,12 in a fixed position.

The support surface 19 is located at a distance H1 from the bottom 25 ofthe hull 6. In the embodiment shown, H1 is around 30 m. In alternativeembodiments, H1 can be between 10 and 60 m. The support surface 19 islocated at a distance H2 from the deck 20. In the embodiment shown, H2is around 15 m. In alternative embodiments, H2 can be between 5 and 30m.

The vessel 1 comprises a ballast system 54 constructed and arranged tolower and raise the vessel 1 relative to the water surface 7. Forlowering the vessel 1, sea water is taken in by the ballast system 54and stored in ballast tanks 60. For raising the vessel 1, the sea wateris released from the ballast system 54. Several outflow openings 55 areprovided to rapidly discharge the water held in the ballast tanks 60.The ballast tanks 60 are located above the water surface 7. This allowsthe use of gravity for rapidly discharging the sea water from theballast system 54. The outflow openings 55 are also located above thewater surface 7 in order to facilitate the rapid removal of sea waterfrom the ballast system 54. The support surface 19 is in use locatedbetween the water surface 7 and 50 m above the water surface 7. Inalternative embodiments, the ballast tanks 60 are located below thewater surface 7. The outflow openings 55 may also be located below thewater surface 7.

The hull 6 comprises a first hull side 21 and an opposite second hullside 22. The support arms 11, 12 extend beyond the hull 6 from the firsthull side 21 and the width W2 of the hull 6 at the second hull side 22is smaller than the width W1 of the hull 6 at the first hull side 21. Inthe direction of the roll axis 8 the hull 6 comprises said smaller widthW2 over a distance of around 40% of the length of the hull 6. In analternative embodiment, the said width W2 extends over a distance ofbetween 20 and 60% of the length of the hull 6. The width W2 of thesecond hull side 22 can be between 20 and 70 m. The width W1 of thefirst hull side 21 can be between 40 and 100 m.

The vessel 1 comprises a propulsion system 53. More specifically, theembodiment shown comprises a dynamic positioning system which is usedfor propulsion. In alternative embodiments, the vessel 1 can compriseany other type of propulsion system, but can also rely on other vesselssuch as tugs in order to move.

The FIGS. 4-11 show a further embodiment of the vessel. A sea platform 2comprising a support structure 4 and a top side 5 is shown. The at leastone part which will be removed and/or installed may relate to the topside and/or the support structure. Said top side and said supportstructure may be partly or fully removed and/or installed.

The sea platform 2 is supported on the seabed by the support structure4. It will be clear that the invention is not only directed to this typeof sea platforms 2. The invention also applies to different types of seaplatforms 2, such as sea platforms 2 with a floating support structure4.

The vessel 1 comprises support units 52 which are attached to thesupport arms 11, 12. The support units 52 are attached to the inner armsurface 14 of the support arms 11, 12. The support units 52 are shown indetail in FIG. 6. The support units 52 form the support surface 19 onwhich said at least one part of the sea platform 2 is placed. In theFIG. 4-11 the top side 5 is the part that will be supported by thesupport arms 11, 12. The support units 52 comprise a first couplingmember 29. The first coupling members 29 are constructed and arranged tocouple with cooperating second coupling members 30 attached on the seaplatform 2. The first coupling members 29 and the second couplingmembers 30 are mating coupling members. In alternative embodiments, thefirst coupling members 29 and the second coupling members 30 can of adifferent type. The support units 52 comprise dampers 56 forming thesupport surface 19. The dampers 56 comprise an elastic material, such asrubber. In other examples, a different type of damper 56 can be used,such as fluid dampers and the like.

The FIGS. 4-11 show an embodiment of the method for removing at least apart of a sea platform comprising a support structure and a top side. InFIG. 4, the vessel 1 is located near the sea platform 2. Second couplingmembers 30 are attached to the sea platform 2. The second couplingmembers 30 are located below the top side 5. The support structure 4 iscut below the second coupling members 30 to allow a removal of the topside 5 from the support structure 4. Part of the support structure 4 isremoved together with the top side 5.

In FIG. 5, the vessel 1 is lowered to a position wherein the firstcoupling members 29 of the vessel 1 are located below the secondcoupling members 30.

In FIG. 7, the support arms 11, 12 are positioned under the top side 5such that the support structure 4 is located between the support arms11, 12. The first coupling members 29 are located directly under thesecond coupling members 30.

In FIG. 8, the support arms 11, 12 are raised relative to the watersurface 7 to fully support the top side 5 with the support arms 11, 12.The first coupling members 29 and the second coupling members 30 arecoupled to each other. The top side 5 is positioned on the supportsurface 19 formed by the support units 52. In an alternative embodiment,the above indicated cut of the support structure 4 is made when the topside is fully supported by the support arms 11, 12.

In FIG. 9, the raising of the support arms 11, 12 is continued to movethe top side 5 at a distance from the support structure 4.

In FIG. 10, the vessel 1 is moved away from the support structure 4 in asubstantially horizontal direction while fully supporting the top side 5with the support arms 11, 12.

In FIG. 11, the top side 5 is transported by the vessel 1 to a quay 49.The vessel 1 is positioned such that the support arms support arms 11,12 supporting the top side are positioned above the quay 49. The topside 5 is subsequently transferred onto the quay 49 by lowering thevessel 1 relative to the water surface 7 with the ballast system 54.

With reference to the FIGS. 4-11, the invention furthermore relates to amethod for installing at least a part of a sea platform comprising asupport structure and top side. Said method comprises;

-   providing a vessel 1 according the invention, such as shown in FIG.    4-11, wherein the top side 5 of the sea platform 2 is fully    supported by the support arms 11, 12,-   positioning the top side 5 above the support structure 4 such that    the support structure 4 is located between the support arms 11, 12,-   lowering the support arms 11, 12 relative to the water surface 7 to    place the top side 5 on the support structure 4,-   continuing the lowering of the support arms 11, 12 to fully transfer    the weight of the top side 5 to the support structure 4 and to move    the support arms 11, 12 at a distance from the top side 5, and-   moving the vessel 1 away from the support structure 4 in a    substantially horizontal direction.

Said method may comprise fully supporting the top side 5 with thesupport arms 11, 12 while the top side 5 is positioned on the supportsurface 19. Said method may comprise fully supporting the top side 5with the support arms 11, 12 via the support units 52.

Said method may comprise attaching cooperating second coupling members30 to the top side 5 and lowering the support arms 11, 12 relative tothe water surface 7 to decouple the first coupling members 29 from thesecond coupling members 30 when the top side 5 is carried by the supportstructure 4.

Said method may comprise connecting the top side 5 to the rest of thesea platform 2, such as the support structure 4, while the support armfully support the top side 5.

Said method may comprise positioning the vessel 1 such that the supportarms 11, 12 supporting the top side 5 are positioned above a quay 49,and transferring the top side 5 from the quay 49 onto the support arms11, 12. The top side 5 may be transferred onto the support arms 11, 12by moving the top side 5 along the support arms 11, 12. The top side 5may be transferred onto the support arms 11, 12 by hoisting the top side5 from the support arms 11, 12 and placing the top side on the quay 49.The top side 5 may be transferred onto the support arms 11, 12 byraising the vessel 1 relative to the water surface 7 with the ballastsystem 54.

The FIGS. 12-14 show a further embodiment of the vessel. A hoistingsystem 32 is attached to the support arms 11, 12. The hoisting system 32is attached to the outboard extending part 33 of the support arms 11,12. The hoisting system 32 comprises a first hoisting member 35, asecond hoisting member 36, a flexible first hoisting line 37 connectingthe first hoisting member 35 with the first support arm 11, a flexiblesecond hoisting line 38 connecting the second hoisting member 36 withthe second support arm 12. The flexible hoisting lines 37, 38 may be ofany suitable type known to the skilled person, such as cables, chains,wires etc. A first line driver 39 is connected to the vessel 1 andconstructed and arranged to take in and pay out the first hoisting line37 in order to move the first hoisting member 35 relative the firstsupport arm 11. A second line driver 40 is connected to the vessel 1 andconstructed and arranged to take in and pay out the second hoisting line38 in order to move the second hoisting member 36 relative the secondsupport arm 12. The first line driver 39 is attached to the firstsupport arm 11 and the second line driver 40 is attached to the secondsupport arm 12. The first line driver 39 and second line driver 40comprise a reeling device, such as a traction winch. In alternativeembodiments, the line driver 39, 40 may be of a different type, such asa strand jack lifting system or a chain jack lifting system.

The first hoisting member 35 and second hoisting member 36 are providedwith first connectors 57 constructed and arranged to in use connect saidhoisting members 35, 36 to cooperating second connectors 58 provided onsaid at least one part of the sea platform 2, more specifically on thesupport structure 4 of the sea platform 2.

The first hoisting member 35 and the second hoisting member 36 comprisean in use substantially horizontal extending hoisting beam 42.

The vessel 1 comprises a further hoisting system 46 which is supportedby the support arms 11, 12. The further hoisting system 46 comprises ahoist driving device 47 constructed and arranged to drive the furtherhoisting device 46 along the support arms 11, 12. Rails 51 are providedon the support arms 11, 12 and the further hoisting system 46 is coupledand movable along said rails 51 via the hoist driving device 47. Thefurther hoisting system 46 comprises a cross beam 48 extending over thedistance between the support arms 11, 12.

The FIGS. 15 and 16 show an alternative embodiment of the vessel of theFIG. 12-14. The first hoisting line 37 is attached to the first supportarm 11 via a first lifting device 44 constructed and arranged to in uselift the first hoisting line 37 above the first support arm 11 in asubstantially vertical direction. The second hoisting line 38 isattached to the second support arm 12 via a second lifting device 45constructed and arranged to in use lift the second hoisting line 38above the second support arm 12 in a substantially vertical direction.Said movement is indicated by arrow 59.

The first lifting device 44 and the second lifting device 45 areconstructed and arranged to lift the first hoisting line 37 and thesecond hoisting line 38 up to a distance of around 30 m above the firstsupport arm 11 and the second support arm 12, respectively. Inalternative embodiments, the first hoisting line 37 and the secondhoisting line 38 are lifted up to a distance between 10 and 50 m abovethe first support arm 11 and the second support arm 12, respectively.

The FIGS. 12-14 show an embodiment of the method for removing at least apart of a sea platform comprising a support structure and a top side. Insaid method the hoisting system 32 is connected to the support structure4 and the support structure 4 is raised with the hoisting system 32 in asubstantially vertical direction while fully supporting the supportstructure 4 with the support arms 11, 12.

In FIG. 12, the vessel 1 and the support structure 4 of the platform 2are shown. The top side 5 has already been removed. In FIG. 13, thefirst hoist member 35 and second hoist member 36 are lowered towards theseabed on which the support structure 4 is positioned. The first hoistmember 35 and second hoist member 36 are connected to the supportstructure 4 at a position below the water surface 7. The first hoistmember 35 and second hoist member 36 may for example be connected to thesupport structure 4 at a position between 10 and several hundreds ofmeters below the water surface 7. The first connectors 57 and the secondconnectors 58 are interconnected.

In FIG. 14, the first hoist member 35 and second hoist member 36 holdingthe support structure 4 are raised towards the water surface 7. Thefirst hoist member 35 and second hoist member 36 may be raised to aposition above the water surface 7.

In the method shown in the FIGS. 15 and 16, the first hoist member 35and second hoist member 36 are raised above the support arms 11, 12.

After the support structure has been raised and is supported by thesupport arms 11, 12, the support structure may be dismantled or thevessel 1 may transport the support structure to a location where it willbe dismantled or re-used.

With reference to the FIGS. 12-16, the invention furthermore relates toa method for installing at least a part of a sea platform comprising asupport structure and top side. Said method comprises;

-   providing a vessel 1 according the invention, such as shown in the    FIG. 12-15, wherein the support structure 4 is connected to the    hoisting system 32 and fully supported by the support arms 11, 12,-   lowering the support structure 4 with the hoisting system 32 in a    substantially vertical direction such that the support structure 4    is placed on the seabed or a foundation provided on the seabed and-   disconnecting the hoisting system 32 from the support structure 4.

Said method may comprise;

-   providing the vessel 1, wherein the first hoist member 35 and second    hoist member 36 are connected to the support structure 4,-   lowering the support structure 4 by lowering the first hoist member    35 and second hoist member 36 towards the seabed,-   disconnecting the first hoist member 35 and second hoist member 36    from the support structure 4 at a positioned below the water surface    7, and-   raising the first hoist member 35 and the second hoist member 36    towards the water surface 7.

Said method may comprise raising the first hoist member 35 and thesecond hoist member 36 to a position above the water surface 7.

Said method may comprise lowering the first hoist member 35 and secondhoist member 36 up to a depth of between 10 and several hundreds ofmeters below the water surface 7.

Said method may comprise providing a vessel according the invention,such as shown in FIGS. 15 and 16, wherein the first hoist member 35 andsecond hoist member 36 are located above the support arms 11, 12 whilebeing connected to support structure 4.

FIG. 17 shows a further embodiment of the vessel. Two heavy liftingcranes 61 are provided on the vessel 1.

FIG. 18 shows a further embodiment of the method. Two parts of the seaplatform are supported by the support arms 11, 12. The top side 5 issupported by the inboard extending part 34 of the support arms 11, 12.The support structure 4 is supported by the outboard extending part 33of the support arms 11, 12.

The FIGS. 19-22 show a further embodiment of the vessel. A top sidesupport 62 is provided on the deck 20 of the vessel 1. The top sidesupport 62 is constructed and arranged to support the top side 5 of thesea platform 2. The top side support 62 is located at the second hullside 22. The top side structure 62 may be located at a distance from thesecond hull side 22. The top side support 62 is located on the deck 20of the vessel 1. The top side support 62 is located at the part of thehull comprising said smaller width W2.

In FIG. 19, a top side 5 is positioned on the top side support 62. Thetop side 5 is fully supported by the top side support 62 located on thedeck 20. A support structure 4 is fully supported by the support arms11, 12. The support structure 4 is connected to the hoisting system 32attached to the support arms 11, 12. The support structure 4 comprisesseveral support legs 63.

In FIG. 20, the support structure 4 is being lowered by the hoistingsystem 32. After the support structure 4 is positioned on the seabed,the hoisting members 35, 36 are subsequently disconnected from thesupport structure 4 and raised to the support arms 11, 12.

In FIG. 21, the support structure 4 is positioned on the seabed and thevessel 1 is positioned such that the top side 5 is located above thesupport structure 4. The hull 6 of the vessel 1 is located between thesupport legs 63. The top side support 62 carrying the top side 5 islowered relative to the water surface 7 to place the top side 5 on thesupport structure 4. Said lowering is continued to fully transfer theweight of the top side 5 to the support structure 4 and to move the topside support 62 at a distance from the top side 5.

In FIG. 22, the top side 5 is fully supported by the support structure 4and the vessel 1 is moving away from the support structure 4 and the topside 5 in a substantially horizontal direction.

The top side support 62 is lowered by lowering the hull 6 of the vessel1 relative to the water surface 7.

With reference to the FIG. 19-22, the invention furthermore relates to amethod wherein a vessel 1 according the invention, such as shown in FIG.19-22, is used to remove a top side 5 from a sea platform 2 comprising asupport structure 4 with several support legs 63 and the top side 5.Said method comprises

-   positioning the top side support 62 under the top side 5 such that    the hull 6 of the vessel 1 is located between the support legs 63 of    the support structure 4,-   raising the top side support 62 relative to the water surface 7 to    fully support the top side 5 with the top side support 62,-   continuing the raising of the top side support 62 to move the top    side 5 at a distance from the support structure 4, and-   moving the vessel 1 away from the support structure 4 in a    substantially horizontal direction while fully supporting the top    side 5 with the top side support 62.

The top side support 62 is raised by raising the hull 6 of the vessel 1relative to the water surface 7.

The support structure 4 can subsequently be removed according to theinvention, such as shown in the FIG. 12-16.

This allows the vessel 1 to remove or install a sea platform comprisinga support structure and top side in one trip.

It is also possible to remove or install a second top side 5, as forexample shown in the FIG. 1-11.

The FIGS. 23-26 show a further embodiment of the vessel. The FIGS. 23-25show a top view of the vessel 1 and FIG. 26 shows a cross sectional viewalong the roll axis 8.

The support arms 11, 12 are movable relative to the hull 6. The supportarms are movable relative to each other. The support arms 11, 12 aremovable in a direction transverse to the roll axis 8. More specifically,the support arms 11, 12 are movable in a direction perpendicular to theroll axis 8.

The support arms 11, 12 are movable along a support trajectory 64. Thesupport trajectory 64 extends transverse to the roll axis 8. Morespecifically, the support trajectory 64 extends perpendicular to theroll axis 8.

The vessel 1 comprises two support rails 65 and the support arms 11, 12are moveable along the support rails 65. The support rails 65 extendtransverse to the roll axis 8. More specifically, the support rails 65extend perpendicular to the roll axis 8. The support rails 65 define thesupport trajectory 64.

The vessel 1 comprises an arm driving system 66 constructed and arrangedto move the support arms 11, 12 relative to the hull 6. The arm drivingsystem 66 moves the support arms 11, 12 along the support trajectory 64.The arm driving system 66 moves the support arms 11, 12 along thesupport rails 65.

The vessel 1 comprises an arm fixating system 67 constructed andarranged to fixate the support arms 11, 12 relative to the hull 6. Thesupport arms 11, 12 are movable from a distance of 10 m between thesupport arms 11, 12 to a distance of 100 m between the support arms 11,12, and vice versa.

The vessel 1 comprises two docking units 70. The vessel 1 may comprise adifferent number of docking units 70. The docking units 70 are attachedto the hull 6. More specifically, the docking units 70 are attached tothe first hull side 21. In other examples of the vessel, at least onedocking unit 70 is attached to the support arms 11, 12, for example tothe inner arm surfaces 14 of the support arms 11, 12.

In FIG. 23, the vessel 1 is positioned near a support structure 4. Thesupport arms 11, 12 are positioned such that the distance between thesupport arms 11, 12 is larger than the width of the support structure 4.

In FIG. 24, the vessel 1 is docked at the support structure 4 via thedocking units 70. The docking units 70 are placed in contact with thesupport structure 4. The vessel 1 is positioned such that the supportstructure 4 is located between the support arms 11, 12.

The support units 52 can be moved along the support arms 11, 12 by thedriving system 31. The support units 52 comprise first coupling members29 and are positioned near second coupling members (not shown) providedon the support structure 4. The support arms 11, 12 are movable in thedirections shown by the arrows 69.

In FIG. 25, the support arms 11, 12 are moved toward each other by thearm driving system 66. The support arms 11, 12 are moved toward thesupport structure 4. The support arms 11, 12 are subsequently fixed in asupport position 68 by the arm fixating system 67. By raising thesupport arms 11, 12 relative to the water surface, the first couplingmembers 29 of the support units 52 couple with the second couplingmembers of the support structure 4. By further raising the support arms11, 12 relative to the water surface, the support structure 4 will belifted which allows the transportation of the support structure 4 by thevessel 1.

In a similar way, the moving support arm 11, 12 can be used to removeand/or install a top side 5. A removal of a top side 5, may for examplebe performed by moving the coupling members 29 and/or the support arms11, 12 relative to the hull 6 such that the first coupling members 29are positioned below second coupling members 30 provided at theunderside of the top side 5. The support arms 11, 12 are subsequentlyraised relative to the water surface to couple the first couplingmembers 29 with the second coupling members 30. The raising of supportarms 11, 12 relative to the water surface is continued to lift the topside 5 from the support structure 4. The vessel 1 is moved away from thesupport structure 4 while fully supporting the top side 5.

An installation of the top side 5, may for example be performed bypositioning the top side 5 above a support structure 4 while the topside 5 is fully supported by the support arms 11, 12. The support arms11, 12 are subsequently lowered relative to the water surface to placethe top side 5 on the support structure 4. The lowering of the supportarms 11, 12 is continued to fully transfer the weight of the top side 5to the support structure 4. The lowering of the support arms 11, 12relative to the water surface may be continued to create a distancebetween the support arms 11, 12 and the top side 5. The support arms 11,12 are moved relative to the hull 6 before the vessel 1 is moved awayfrom the support structure 4.

With reference to the FIG. 23-26, the invention furthermore relates to amethod for removing and/or installing at least one part of a seaplatform 2 comprising a support structure 4 and a top side 5, whereinthe method comprises the feature of moving the support arms 11, 12relative to the hull 6. The method may comprise the feature of movingthe support arms 11, 12 relative to each other. The method may comprisethe feature of moving the support arms 11, 12 towards each other. Themethod may comprise the feature of moving the support arms 11, 12 awayfrom each other. The method may comprise the feature of moving thesupport arms 11, 12 in a direction transverse to the roll axis 8. Themethod may comprise the feature of moving the support arms 11, 12 in adirection perpendicular to the roll axis 8. The method may comprise thefeature of moving the support arms 11, 12 along the support trajectory64. The method may comprise the feature of moving the support arms 11,12 along the support rail 65. The method may comprise the feature ofmoving the support arms 11, 12 to match the dimensions of the top side 5which in use will be supported by the support arms 11, 12. The methodmay comprise the feature of moving the support arms 11, 12 to match thedimensions of the support structure 4 which in use will be supported bythe support arms 11, 12. The method may comprise the feature of fixatingthe support arms 11, 12 relative to the hull 6 in a support position 68.The method may comprise the feature of docking the vessel 1 at thesupport structure 4 via the at least one docking unit 70. The method maycomprise the feature of moving the support arms 11, 12 relative to thehull after the docking of the vessel 1. The method may comprise thefeature of fixating the support arms 11, 12 relative to the hull 6 afterthe docking of the vessel 1.

FIG. 27 shows a further embodiment of the vessel. The hoisting system 32is constructed and arranged to move said at least one part along thesupport arms 11, 12. The hoisting system 32 is constructed and arrangedto move said at least one part along the deck 20 of the vessel 11. Thedriving system 31 is constructed and arranged to move the hoistingsystem 32 along the support arms 11, 12. The driving system 31 isconstructed and arranged to move the hoist members 35, 36 along thesupport arms 11, 12.

The support arms 11, 12 comprise rails 51 and the driving system 31moves the hoisting system 31 along said rails 51. The rails 51 extendsubstantially parallel to the roll axis 8 of the vessel 1.

With reference to the FIG. 27, the invention furthermore relates to amethod for removing and/or installing at least one part of a seaplatform comprising a support structure and a top side, wherein themethod comprises the feature of moving said at least one part supportedby the support arms 11, 12 along the deck 20 of the vessel 1. The methodmay comprise the feature of moving said at least one part supported bythe support arms 11, 12 in the direction of the roll axis 8 of thevessel 1. The method may comprise the feature of moving said at leastone part carried by the hoisting system 32 along said support arms 11,12 with the driving system 31. The method may comprise the feature ofmoving said at least one part carried by the hoisting system 21 alongthe rails 51. The method may comprise the feature of moving the hoistmembers 35, 36 along the support arms 11, 12 with the driving system 31while carrying the said at least one part. The method may comprise thefeature of placing said at least one part carried by the hoisting system32 on the deck 20 of the vessel 1.

The method may comprise the feature of transferring said at least onepart from the vessel 1 onto a quay 49 by positioning the second hullside 22 adjacent to the quay 49 and moving said at least one part fromthe vessel 1 to the quay 49 while moving over the second hull side 22.

The method may comprise the feature of transferring said at least onepart from a quay 49 onto the vessel 1 by positioning the second hull 22side adjacent to the quay 49 and moving said at least one part from thequay 49 to the vessel 1 while moving over the second hull side 22.

Said at least one part may be the support structure 4. Said at least onepart may be the top side 5.

The method may comprise the feature of removing the support structure 4while the vessel 1 carries the top side 5. The method may comprise thefeature of removing the support structure 4 while the vessel 1 carries afurther support structure 4. The method may comprise the feature ofremoving the top side 5 while the vessel carries a further top side 5.

The method may comprise the feature of installing the support structure4 while the vessel carries the top side 5. The method may comprise thefeature of installing the support structure 4 while the vessel carries afurther support structure 4. The method may comprise the feature ofinstalling the top side 5 while the vessel carries a further top side 5.

FIG. 28 shows a further embodiment of the vessel. The hoisting system 32comprises a first hoisting member 35, a second hoisting member 36, athird hoisting member 73, and a fourth hoisting member 74. A flexiblefirst hoisting line 37 connects the first hoisting member 35 with thefirst support arm 11. A flexible second hoisting line 38 connects thesecond hoisting member 36 with the second support arm 12. A flexiblethird hoisting line 75 connects the third hoisting member 73 with thefirst support arm 11. A flexible fourth hoisting line 76 connects thefourth hoisting member 74 with the second support arm 12.

The hoisting system 32 comprises a first line driver 39 connected to thefirst hoisting line 37, a second line driver 40 connected to the secondhoisting line 38, a third line driver 77 connected to the third hoistingline 75 and a fourth line driver 78 connected to the fourth hoistingline 76. The first line driver 39 is attached to the first support arm11, the second line driver 40 is attached to the second support arm 12,the third line driver 77 is attached to the first support arm 11 and thefourth line driver 78 is attached to the second support arm 12.

The support structure 4 is of the type on which a top side comprising awind turbine is placed. Two further support structures 4 are located onthe deck 20 of the vessel 1.

The following clauses present a further description of the vessel,method and use according to the invention.

Clause 1. Vessel for removal and/or installation of at least one part ofa sea platform comprising a support structure and a top side, saidvessel comprising a hull and two support arms located at a distance fromeach other and attached to the hull, wherein the support arms in useextend beyond the hull in a substantially horizontal direction.

Clause 2. Vessel according to clause 1, wherein the support arms areconstructed and arranged to in use fully support said at least one partof the sea platform.

Clause 3. Vessel according to clause 1 or 2, wherein the support armsextend over a distance between 10 and 100 m beyond the hull.

Clause 4. Vessel according to any of the preceding clauses, wherein thesupport arms extend along the hull over a distance between 10 and 100%of the length of the hull.

Clause 5. Vessel according to any of the preceding clauses, wherein thedistance between the support arms is between 10 and 100 m.

Clause 6. Vessel according to any of the preceding clauses, wherein thesupport arms are located above the water surface when carrying said atleast one part of the sea platform.

Clause 7. Vessel according to any of the preceding clauses, wherein thesupport arms extend substantially parallel to each other.

Clause 8. Vessel according to any of the preceding clauses, wherein thevessel comprises a roll axis.

Clause 9. Vessel according to clause 8, wherein the support arms extendsubstantially parallel to the roll axis.

Clause 10. Vessel according to any of the preceding clauses, wherein thesupport arms are provided with a driving system constructed and arrangedto in use move said at least one part carried by the support arms alongsaid support arms.

Clause 11. Vessel according to any of the preceding clauses, wherein thesupport arms form a support surface on which the said at least one partin use is placed.

Clause 12. Vessel according to clause 11, wherein the vessel comprises adeck and the support surface in use is located above the deck.

Clause 13. Vessel according to any of the preceding clauses, wherein thesupport arms comprise an upper arm surface, a second arm end connectedto the hull and an inclined surface extending from the upper arm surfaceto the deck.

Clause 14. Vessel according to any of the clauses 11-13, wherein thesupport surface in use is located between the water surface and 50 mabove the water surface.

Clause 15. Vessel according to any of the clauses 11-14, wherein thesupport surface is located at a distance of between 10 and 60 m from thebottom of the hull.

Clause 16. Vessel according to any of the clauses 11-15, wherein thesupport surface is located at a distance of between 5 and 30 m from thedeck.

Clause 17. Vessel according to any of the preceding clauses, wherein thevessel comprises a ballast system constructed and arranged to lower andraise the vessel relative to the water surface.

Clause 18. Vessel according to clause 17, wherein the ballast systemcomprises at least one ballast tank in which water received by theballast system is held.

Clause 19. Vessel according to clause 18, wherein the ballast tanks arelocated in the support arms.

Clause 20. Vessel according to clause 19, wherein the ballast tanks arelocated in the inboard extending part of the support arms.

Clause 21. Vessel according to any of the clauses 18-20, wherein theballast tanks in use are positioned above the water surface.

Clause 22. Vessel according to any of the clauses 18-21, wherein theballast system comprise outflow openings which are in fluidcommunication with the ballast tanks to discharge water held by saidballast tanks and the outflow openings are in use located above thewater surface.

Clause 23. Vessel according to any of the preceding clauses, whereinsaid at least one part of the sea platform comprises the top side.

Clause 24. Vessel according to any of the preceding clauses, whereinsupport units are attached to the support arms.

Clause 25. Vessel according to any of the preceding clauses, whereinsupport units are attached to the hull.

Clause 26. Vessel according to clause 24 or 25, wherein the supportunits form the support surface.

Clause 27. Vessel according to any of the clauses 24-26, wherein thesupport units comprise a first coupling member.

Clause 28. Vessel according to clause 27, wherein the first couplingmembers are constructed and arranged to couple with cooperating secondcoupling members attached to said at least one part.

Clause 29. Vessel according to any of the clauses 24-28, wherein thesupport units comprise dampers forming the support surface.

Clause 30. Vessel according to clause 29, wherein dampers comprise anelastic material, such as rubber.

Clause 31. Vessel according to any of the clauses 10-30, wherein thedriving system is constructed and arranged to move at least part of thesupport units along the support arms.

Clause 32. Vessel according to any of the preceding clauses, wherein thehull comprises a first hull side and an opposite second hull side, thesupport arms extend beyond the hull from the first hull side.

Clause 33. Vessel according to clause 32, wherein the width of the hullat the second hull side is smaller than the width of the hull at thefirst hull side.

Clause 34. Vessel according to clause 33, wherein in the direction ofthe roll axis the hull comprises said smaller width over a distancebetween 20 and 60% of the length of the hull.

Clause 35. Vessel according to any of the clauses 32-34, wherein thewidth of the second hull side is between 20 and 70 m.

Clause 36. Vessel according to any of the clauses 32-35, wherein thewidth of the first hull side is between 40 and 100 m.

Clause 37. Vessel according to any of the preceding clauses, wherein atop side support is provided on the deck of the vessel.

Clause 38. Vessel according to clause 37, wherein the top side supportis located at the second hull side.

Clause 39. Vessel according to clause 38, wherein the top side supportis located at the part of the hull comprising said smaller width.

Clause 40. Vessel according to any of the preceding clauses, wherein ahoisting system is attached to the support arms.

Clause 41. Vessel according to clause 40, wherein the hoisting system isattached to the outboard extending part of the support arms.

Clause 42. Vessel according to any of the preceding clauses, whereinsaid at least one part of the sea platform comprises the supportstructure.

Clause 43. Vessel according to any of the clauses 40-42, wherein thesupport arms comprise a first support arm and a second support arm andthe hoisting system comprises;

-   a first hoisting member,-   a second hoisting member,-   a flexible first hoisting line connecting the first hoisting member    with the first support arm,-   a flexible second hoisting line connecting the second hoisting    member with the second support arm, and-   at least one line driver connected to the vessel and constructed and    arranged to take in and pay out the first hoisting line and second    hoisting line in order to move the first hoisting member and the    second hoisting member relative the first support arm and the second    support arm, respectively.

Clause 44. Vessel according to clause 43, wherein the hoisting systemcomprises;

-   a third hoisting member,-   a fourth hoisting member,-   a flexible third hoisting line connecting the third hoisting member    with the first support arm,-   a flexible fourth hoisting line connecting the fourth hoisting    member with the second support arm, and    the at least one line driver is constructed and arranged to take in    and pay out the third hoisting line and fourth hoisting line in    order to move the third hoisting member and the fourth hoisting    member relative the first support arm and the second support arm,    respectively.

Clause 45. Vessel according to clause 43 or 44, wherein the hoistingsystem comprises a separate line driver connected to each hoisting line.

Clause 46. Vessel according to clause 43-45, wherein the hoisting systemcomprises a first line driver connected to the first hoisting line and asecond line driver connected to the second hoisting line.

Clause 47. Vessel according to clause 46, wherein the first line driveris attached to the first support arm and the second line driver isattached to the second support arm.

Clause 48. Vessel according to any of the clauses 43-47, wherein thefirst hoisting member and second hoisting member are provided withconnectors constructed and arranged to in use connect said hoistingmembers to the support structure.

Clause 49. Vessel according to any of the clauses 43-48, wherein thefirst hoisting member and the second hoisting member comprise an in usesubstantially horizontal extending hoisting beam.

Clause 50. Vessel according to any of the clauses 43-49, wherein thefirst hoisting line is attached to the first support arm via a firstlifting device constructed and arranged to in use lift the firsthoisting line above the first support arm in a substantially verticaldirection and the second hoisting line is attached to the second supportarm via a second lifting device constructed and arranged to in use liftthe second hoisting line above the second support arm in a substantiallyvertical direction.

Clause 51. Vessel according to clause 50, wherein the first liftingdevice and the second lifting device are constructed and arranged tolift the first hoisting line and the second hoisting line up to adistance of between 10 and 50 m above the first support arm and thesecond support arm, respectively.

Clause 52. Vessel according to any of the clauses 44-51, wherein thehoisting system comprises a third line driver connected to the thirdhoisting line and a fourth line driver connected to the fourth hoistingline.

Clause 53. Vessel according to clause 52, wherein the third line driveris attached to the first support arm and the fourth line driver isattached to the second support arm.

Clause 54. Vessel according to any of the clauses 44-53, wherein thethird hoisting member and fourth hoisting member are provided withconnectors constructed and arranged to in use connect said hoistingmembers to the support structure.

Clause 55. Vessel according to any of the clauses 44-54, wherein thethird hoisting line is attached to the first support arm via a thirdlifting device constructed and arranged to in use lift the thirdhoisting line above the first support arm in a substantially verticaldirection and the fourth hoisting line is attached to the second supportarm via a fourth lifting device constructed and arranged to in use liftthe fourth hoisting line above the second support arm in a substantiallyvertical direction.

Clause 56. Vessel according to clause 55, wherein the third liftingdevice and the fourth lifting device are constructed and arranged tolift the third hoisting line and the fourth hoisting line up to adistance of between 10 and 50 m above the first support arm and thesecond support arm, respectively.

Clause 57. Vessel according to any of the clauses 40-56, wherein thehoisting system is constructed and arranged to move said at least onepart along the support arms.

Clause 58. Vessel according to any of the clauses 40-57, wherein thehoisting system is constructed and arranged to move said at least onepart along the deck of the vessel.

Clause 59. Vessel according to any of the clauses 40-58, wherein thedriving system is constructed and arranged to move the hoisting systemalong the support arms.

Clause 60. Vessel according to any of the clauses 43-59, wherein thedriving system is constructed and arranged to move the hoist membersalong the support arms.

Clause 61. Vessel according to any of the clauses 40-60, wherein thesupport arms comprise rails and the driving system moves the hoistingsystem along said rails.

Clause 62. Vessel according to any of the clauses 40-61, wherein eachsupport arm comprises a rail and the driving system moves the hoistingsystem along said rails.

Clause 63. Vessel according to clause 61 or 62, wherein the rails extendsubstantially parallel to the roll axis of the vessel.

Clause 64. Vessel according to any of the preceding clauses, wherein thevessel comprises a further hoisting system which is supported by thesupport arms and the further hoisting system comprises a hoist drivingdevice to drive the further hoisting device along the support arms.

Clause 65. Vessel according to clause 64, wherein the further hoistingsystem comprises a cross beam extending over the distance between thesupport arms.

Clause 66. Vessel according to any of the preceding clauses, wherein thevessel comprises a heavy lifting crane positioned on the deck.

Clause 67. Vessel according to any of the preceding clauses, wherein thesupport arms are movable relative to the hull.

Clause 68. Vessel according to any of the preceding clauses, wherein thesupport arms are movable relative to each other.

Clause 69. Vessel according to any of the preceding clauses, wherein thesupport arms are movable in a direction transverse to the roll axis.

Clause 70. Vessel according to any of the preceding clauses, wherein thesupport arms are movable in a direction perpendicular to the roll axis.

Clause 71. Vessel according to any of the preceding clauses, wherein thesupport arms are movable along a support trajectory.

Clause 72. Vessel according to clause 71, wherein the support trajectoryextends transverse to the roll axis.

Clause 73. Vessel according to clause 71, wherein the support trajectoryextends perpendicular to the roll axis.

Clause 74. Vessel according to any of the preceding clauses, wherein thevessel comprises a support rail and the support arms are moveable alongthe support rail.

Clause 75. Vessel according to clause 74, wherein the support railextends transverse to the roll axis.

Clause 76. Vessel according to clause 74, wherein the support railextends perpendicular to the roll axis.

Clause 77. Vessel according to any of the clauses 74-76, wherein thesupport rail defines the support trajectory.

Clause 78. Vessel according to any of the preceding clauses, wherein thevessel comprises an arm driving system constructed and arranged to movethe support arms relative to the hull.

Clause 79. Vessel according to clause 78, wherein the arm driving systemmoves the support arms along the support trajectory.

Clause 80. Vessel according to clause 78 or 79, wherein the arm drivingsystem moves the support arms along the support rails.

Clause 81. Vessel according to any of the preceding clauses, wherein thevessel comprises an arm fixating system constructed and arranged tofixate the support arms relative to the hull.

Clause 82. Vessel according to any of the clauses 67-81, wherein thesupport arms are movable from a distance of 10 m between the supportarms to a distance of 100 m between the support arms, and vice versa.

Clause 83. Vessel according to any of the preceding clauses, wherein thevessel comprises at least one docking unit.

Clause 84. Vessel according to clause 83, wherein at least one dockingunit is attached to the support arms.

Clause 85. Vessel according to clause 84, wherein at least one dockingunit is attached to the inner arm surfaces of the support arms.

Clause 86. Vessel according to any of the clauses 83-85, wherein atleast one docking unit is attached to the hull.

Clause 87. Vessel according to clause 86, wherein at least one dockingunit is attached to the first hull side.

Clause 88. Vessel according to any of the preceding clauses, wherein thetop side comprises equipment constructed and arranged to exploit oiland/or gas from the seabed.

Clause 89. Vessel according to any of the preceding clauses, wherein thetop side comprises a drilling system constructed and arranged to drillin the seabed.

Clause 90. Vessel according to any of the preceding clauses, wherein thetop side comprises a wind turbine.

Clause 91. Method for removing at least a part of a sea platformcomprising a support structure and a top side, which method comprises;

-   providing a vessel according to any of the preceding clauses,-   positioning the support arms under the top side such that the    support structure is located between the support arms,-   raising the support arms relative to the water surface to fully    support the top side with the support arms,-   continuing the raising of the support arms to move the top side at a    distance from the support structure and-   moving the vessel away from the support structure in a substantially    horizontal direction while fully supporting the top side with the    support arms.

Clause 92. Method according to clause 91, wherein the provided vesselcomplies with any of the clauses 11-90 and the method comprises fullysupporting the top side with the support arms while the top side ispositioned on the support surface.

Clause 93. Method according to clause 91 or 92, wherein the providedvessel complies with any of the clauses 24-90 and the method comprisesfully supporting the top side with the support arms via the supportunits.

Clause 94. Method according to any of the clauses 91-93, wherein theprovided vessel complies with any of the clauses 67-90 and wherein themethod comprises moving the support arms relative to the hull before thesupport arms support the top side.

Clause 95. Method according to any of the clauses 91-94, wherein theprovided vessel complies with any of the clauses 67-90 and wherein themethod comprises moving the support arms relative to the hull after thesupport arms are positioned under the top side.

Clause 96. Method according to any of the clauses 91-95, wherein theprovided vessel complies with any of the clauses 67-90 and wherein themethod comprises fixating the support arms relative to the hull in asupport position before the support arms fully support the top side.

Clause 97. Method according to any of the clauses 91-96, wherein theprovided vessel complies with any of the clauses 67-90 and wherein themethod comprises fixating the support arms relative to the hull in asupport position after the support arms are positioned under the topside.

Clause 98. Method according to any of the clauses 91-97, wherein theprovided vessel complies with any of the clauses 27-90 and the methodcomprises attaching cooperating second coupling members to the top side.

Clause 99. Method according to clause 98, wherein the method comprisesraising the support arms relative to the water surface to couple thefirst coupling members with the second coupling members.

Clause 100. Method according to clause 98 or 99, wherein the providedvessel complies with any of the clauses 67-90 and the method comprisesfixating the support arms relative to the hull in a support positionbefore the first coupling members are coupled with the second couplingmembers.

Clause 101. Method according to any of the clauses 98-100, wherein theprovided vessel complies with any of the clauses 67-90 and the methodcomprises moving the support arms relative to the hull to couple thefirst coupling members with the second coupling members.

Clause 102. Method according to any of the clauses 98, 99, 101, whereinthe provided vessel complies with any of the clauses 67-90 and themethod comprises fixating the support arms relative to the hull in asupport position after the first coupling members are coupled with thesecond coupling members.

Clause 103. Method according to any of the clauses 91-102, wherein theprovided vessel complies with any of the clauses 83-90 and the methodcomprises docking the vessel at the support structure via the at leastone docking unit to positioning the support arms under the top side suchthat the support structure is located between the support arms,

Clause 104. Method according to any of the clauses 91-103, wherein theprovided vessel complies with any of the clauses 83-90 and the methodcomprises docking the vessel at the support structure via the at leastone docking unit before the support arms support the top side.

Clause 105. Method according to any of the clauses 91-104, wherein theprovided vessel complies with any of the clauses 83-90 and the methodcomprises docking the vessel at the support structure via the at leastone docking unit before the support arms are raised relative to thewater surface.

Clause 106. Method according to any of the clauses 91-105, wherein themethod comprises disconnecting the top side from the rest of the seaplatform while the support arms fully support the top side.

Clause 107. Method according to any of the clauses 91-106, wherein themethod comprises

-   positioning the vessel such that the support arms supporting the top    side are positioned above a quay, and-   transferring the top side onto the quay.

Clause 108. Method according to clause 107, wherein the top side istransferred onto the quay by moving the top side along the support arms.

Clause 109. Method according to clause 107 or 108, wherein the top sideis transferred onto the quay by hoisting the top side from the supportarms and placing the top side on the quay.

Clause 110. Method according to any of the clauses 107-109, wherein thetop side is transferred onto the quay by lowering the support arms.

Clause 111. Method according to any of the clauses 107-110, wherein theprovided vessel complies with any of the clauses 67-90 and the top sideis transferred onto the quay by moving the support arm relative to thehull.

Clause 112. Method for removing at least part of a sea platformcomprising a support structure and a top side, which method comprises;

-   providing a vessel according to any of the clauses 40-90,-   connecting the hoisting system to the support structure, and-   raising the support structure with the hoisting system in a    substantially vertical direction while fully supporting the support    structure with the support arms.

Clause 113. Method according to any of the clauses 91-111, wherein theprovided vessel complies with any of the clauses 40-90 and the methodcomprises

-   connecting the hoisting system to the support structure, and-   raising the support structure with the hoisting system in a    substantially vertical direction while fully supporting the support    structure with the support arms.

Clause 114. Method according to any of the clauses 112 or 113, whereinthe provided vessel complies with any of the clauses 43-90 and themethod comprises

-   lowering the first hoist member and second hoist member towards the    seabed,-   connecting the first hoist member and second hoist member to the    support structure at a position below the water surface, and-   raising the first hoist member and second hoist member towards the    water surface.

Clause 115. Method according to clause 115, wherein the method comprisesraising the first hoist member and second hoist member to a positionabove the water surface.

Clause 116. Method according to clause 114 or 115, wherein the providedvessel complies with any of the clauses 50-90 and the method comprisesraising the first hoist member and second hoist member above the supportarms.

Clause 117. Method according to any of the clauses 112-116, wherein theprovided vessel complies with any of the clauses 44-90 and the methodcomprises

-   lowering the third hoist member and fourth hoist member towards the    seabed,-   connecting the third hoist member and fourth hoist member to the    support structure at a position below the water surface, and-   raising the third hoist member and fourth hoist member towards the    water surface.

Clause 118. Method according to clause 117, wherein the method comprisesraising the third hoist member and fourth hoist member to a positionabove the water surface.

Clause 119. Method according to clause 117 or 118, wherein the providedvessel complies with any of the clauses 55-90 and the method comprisesraising the third hoist member and fourth hoist member above the supportarms.

Clause 120. Method according to any of the clauses 112-119, wherein themethod comprises dismantling the support structure while being supportedby the support arms.

Clause 121. Method according to any of the clauses 112-120, wherein theprovided vessel complies with any of the clauses 67-90 and the methodcomprises moving the support arms relative to the hull before thesupport structure is raised with the hoisting system.

Clause 122. Method according to any of the clauses 112-121, wherein theprovided vessel complies with any of the clauses 67-90 and the methodcomprises fixating the support arms relative to the hull before thesupport structure is raised with the hoisting system.

Clause 123. Method according to any of the clauses 112-122, wherein theprovided vessel complies with any of the clauses 67-90 and the methodcomprises docking the vessel at the support structure via at least onedocking unit before the support structure is raised with the hoistingsystem.

Clause 124. Method for removing at least a part of a sea platformcomprising a support structure and a top side, wherein the supportstructure comprise support legs and the method comprises;

-   providing a vessel which complies with any of the clauses 37-90,-   positioning the top side support under the top side such that the    hull of the vessel is located between the support legs,-   raising the top side support relative to the water surface to fully    support the top side with the top side support,-   continuing the raising of the top side support to move the top side    at a distance from the support structure and-   moving the vessel away from the support structure in a substantially    horizontal direction while fully supporting the top side with the    top side support.

Clause 125. Method according to any of the clauses 112-123, wherein theprovided vessel complies with any of the clauses 37-90, the supportstructure of the sea platform comprises support legs and the methodcomprises

-   positioning the top side support under the top side such that the    hull of the vessel is located between the support legs,-   raising the top side support relative to the water surface to fully    support the top side with the top side support,-   continuing the raising of the top side support to move the top side    at a distance from the support structure and-   moving the vessel away from the support structure in a substantially    horizontal direction while fully supporting the top side with the    top side support.

Clause 126. Method according to clause 124 or 125, wherein the methodcomprises fully supporting the top side with the top side supportlocated on the deck of the vessel.

Clause 127. Method according to any of the clauses 124-126, wherein themethod comprises raising the top side support by raising the hull of thevessel relative to the water surface.

Clause 128. Method for installing at least a part of a sea platformcomprising a support structure and a top side, which method comprises;

-   providing a vessel according to any of the clauses 1-90, wherein the    top side of the sea platform is fully supported by the support arms,-   positioning the top side above the support structure such that the    support structure is located between the support arms,-   lowering the support arms relative to the water surface to place the    top side on the support structure,-   continuing the lowering of the support arms to fully transfer the    weight of the top side to the support structure and to move the    support arms at a distance from the top side and-   moving the vessel away from the support structure in a substantially    horizontal direction.

Clause 129. Method according to clause 128, wherein the provided vesselcomplies with any of the clauses 11-90 and the method comprises fullysupporting the top side with the support arms while the top side ispositioned on the support surface.

Clause 130. Method according to clause 128 or 129, wherein the providedvessel complies with any of the clauses 24-90 and the method comprisesfully supporting the top side with the support arms via the supportunits.

Clause 131. Method according to any of the clauses 128-130, wherein themethod comprises moving the support arms relative to the hull after thetransfer of the weight of the top side to the support structure.

Clause 132. Method according to any of the clauses 128-131, wherein theprovided vessel complies with any of the clauses 27-90 and cooperatingsecond coupling members are attached to the top side and coupled to thefirst coupling members.

Clause 133. Method according to clause 132, wherein the method compriseslowering the support arms relative to the water surface to decouple thefirst coupling members from the second coupling members.

Clause 134. Method according to clause 132 or 133, wherein the methodcomprises moving the support arms relative to the hull to decouple thefirst coupling members from the second coupling members.

Clause 135. Method according to any of the clauses 128-134, wherein theprovided vessel complies with any of the clauses 83-90 and the methodcomprises docking the vessel at the support structure via the at leastone docking unit to positioning the top side above the support structuresuch that the support structure is located between the support arms.

Clause 136. Method according to any of the clauses 128-135, wherein theprovided vessel complies with any of the clauses 83-90 and the methodcomprises docking the vessel at the support structure via at least onedocking unit before the support arms are lowered relative to the watersurface.

Clause 137. Method according to any of the clauses 128-136, wherein themethod comprises fully supporting the top side with the support arms bypositioning the vessel such that the support arms are positioned above aquay on which the top side is located and transferring the top side onto the support arms.

Clause 138. Method according to clause 137, wherein the top side istransferred onto the support arms by moving the top side along thesupport arms.

Clause 139. Method according to clause 137 or 138, wherein the top sideis transferred onto the support arms by hoisting the top side from thequay and placing the top side on the support arms.

Clause 140. Method according to any of the clauses 137-139, wherein thetop side is transferred onto the support arm by raising the supportarms.

Clause 141. Method according to any of the clauses 137-140, wherein theprovided vessel complies with any of the clauses 67-90 and the top sideis transferred onto the support arms by moving the support arm relativeto the hull.

Clause 142. Method for installing at least a part of a sea platformcomprising a support structure and top side, which method comprises;

-   providing a vessel according to any of the clauses 40-90, wherein    the support structure is connected to the hoisting system and fully    supported by the support arms,-   lowering the support structure with the hoisting system in a    substantially vertical direction such that the support structure is    placed on the seabed or a foundation provided on the seabed and-   disconnecting the hoisting system from the support structure.

Clause 143. Method according to any of the clauses 128-141, wherein theprovided vessel complies with any of the clauses 40-90, the supportstructure is connected to the hoisting system and fully supported by thesupport arms, and the method comprises

-   lowering the support structure with the hoisting system in a    substantially vertical direction such that the support structure is    placed on the seabed or a foundation provided on the seabed, and-   disconnecting the hoisting system from the support structure.

Clause 144. Method according to clause 142 or 143, wherein the providedvessel complies with any of the clauses 43-90, the first hoist memberand second hoist member are connected to the support structure, and themethod comprises;

-   lowering the support structure by lowering the first hoist member    and second hoist member towards the seabed, and-   disconnecting the first hoist member and second hoist member from    the support structure at a positioned below the water surface, and-   raising the first hoist member and the second hoist member towards    the water surface.

Clause 145. Method according to clause 144, wherein the method comprisesraising the first hoist member and the second hoist member to a positionabove the water surface.

Clause 146. Method according to clause 144 or 145, wherein the providedvessel complies with any of the clauses 50-90 and the first hoist memberand second hoist member are located above the support arms while beingconnected to support structure.

Clause 147. Method according to any of the clauses 144-146, wherein theprovided vessel complies with any of the clauses 44-90, the third hoistmember and fourth hoist member are connected to the support structure,and the method comprises;

-   lowering the support structure by lowering the third hoist member    and fourth hoist member towards the seabed, and-   disconnecting the third hoist member and fourth hoist member from    the support structure at a positioned below the water surface, and-   raising the third hoist member and the fourth hoist member towards    the water surface.

Clause 148. Method according to clause 147, wherein the method comprisesraising the third hoist member and the fourth hoist member to a positionabove the water surface.

Clause 149. Method according to clause 147 or 148, wherein the providedvessel complies with any of the clauses 55-90 and the third hoist memberand fourth hoist member are located above the support arms while beingconnected to support structure.

Clause 150. Method for installing at least a part of a sea platformcomprising a support structure and top side, wherein the supportstructure comprise support legs and the method comprises;

-   providing a vessel which complies with any of the clauses 37-90, and    wherein the top side of the sea platform is fully supported by the    top side support,-   positioning the top side above the support structure such that the    hull of the vessel is located between the support legs,-   lowering the top side support relative to the water surface to place    the top side on the support structure,-   continuing the lowering of the top side support to fully transfer    the weight of the top side to the support structure and to move the    top side support at a distance from the top side and-   moving the vessel away from the support structure in a substantially    horizontal direction.

Clause 151. Method according to any of the clauses 142-149, wherein theprovided vessel complies with any of the clauses 37-90, the top side ofthe sea platform is fully supported by the top side support, and themethod comprises

-   positioning the top side above the support structure such that the    hull of the vessel is located between the support legs,-   lowering the top side support relative to the water surface to place    the top side on the support structure,-   continuing the lowering of the top side support to fully transfer    the weight of the top side to the support structure and to move the    top side support at a distance from the top side and-   moving the vessel away from the support structure in a substantially    horizontal direction.

Clause 152. Method according to clause 150 or 151, wherein the methodcomprises fully supporting the top side with the top side supportlocated on the deck of the vessel.

Clause 153. Method according to any of the clauses 150-151, wherein themethod comprises lowering the top side support by lowering the hull ofthe vessel relative to the water surface.

Clause 154. Method according to any of the clauses 91-153, wherein themethod comprises fully supporting at least one part of the sea platformwith the outboard extending part of the support arms.

Clause 155. Method according to any of the clauses 91-154, wherein themethod comprises fully supporting at least one part of the sea platformwith the inboard extending part of the support arms.

Clause 156. Method according to any of the clauses 91-155, wherein atleast two parts of the sea platform are supported by the support arms

Clause 157. Method according to any of the clauses 91-156, wherein themethod comprises raising the support arms relative to the water surfaceby raising the hull relative to the water surface.

Clause 158. Method according to any of the clauses 91-157, wherein themethod comprises lowering the support arms relative to the water surfaceby lowering the hull relative to the water surface.

Clause 159. Method according to any of the clauses 91-158, wherein theprovided vessel complies with any of the clauses 67-90 and the methodcomprises moving the support arms relative to the hull.

Clause 160. Method according to any of the clauses 91-159, wherein theprovided vessel complies with any of the clauses 67-90 and the methodcomprises moving the support arms relative to each other.

Clause 161. Method according to any of the clauses 91-160, wherein theprovided vessel complies with any of the clauses 67-90 and the methodcomprises moving the support arms towards each other.

Clause 162. Method according to any of the clauses 91-161, wherein theprovided vessel complies with any of the clauses 67-90 and the methodcomprises moving the support arms away from each other.

Clause 163. Method according to any of the clauses 91-162, wherein theprovided vessel complies with any of the clauses 67-90 and the methodcomprises moving the support arms in a direction transverse to the rollaxis.

Clause 164. Method according to any of the clauses 91-162, wherein theprovided vessel complies with any of the clauses 67-90 and the methodcomprises moving the support arms in a direction perpendicular to theroll axis.

Clause 165. Method according to any of the clauses 91-164, wherein theprovided vessel complies with any of the clauses 71-90 and the methodcomprises moving the support arms along the support trajectory.

Clause 166. Method according to any of the clauses 91-165, wherein theprovided vessel complies with any of the clauses 74-90 and the methodcomprises moving the support arms along the support rail.

Clause 167. Method according to any of the clauses 91-166, wherein theprovided vessel complies with any of the clauses 67-90 and the methodcomprises moving the support arms to match the dimensions of the topside which in use will be supported.

Clause 168. Method according to any of the clauses 91-167, wherein theprovided vessel complies with any of the clauses 67-90 and the methodcomprises moving the support arms to match the dimensions of the supportstructure which in use will be supported.

Clause 169. Method according to any of the clauses 91-168, wherein theprovided vessel complies with any of the clauses 67-90 and the methodcomprises fixating the support arms relative to the hull in a supportposition.

Clause 170. Method according to any of the clauses 91-169, wherein theprovided vessel complies with any of the clauses 83-90 and the methodcomprises docking the vessel at the support structure via the at leastone docking unit.

Clause 171. Method according to any of the clauses 91-170, wherein theprovided vessel complies with any of the clauses 83-90 and the methodcomprises moving the support arms relative to the hull after the dockingof the vessel.

Clause 172. Method according to any of the clauses 91-171, wherein theprovided vessel complies with any of the clauses 83-90 and the methodcomprises fixating the support arms relative to the hull after thedocking of the vessel.

Clause 173. Method according to any of the clauses 91-172, wherein themethod comprises moving said at least one part supported by the supportarms along said support arms.

Clause 174. Method according to any of the clauses 91-173, wherein themethod comprises moving said at least one part supported by the supportarms along the deck of the vessel.

Clause 175. Method according to any of the clauses 91-174, wherein theprovided vessel complies with any of the clauses 8-90 and the methodcomprises moving said at least one part supported by the support arms inthe direction of the roll axis of the vessel.

Clause 176. Method according to any of the clauses 91-175, wherein theprovided vessel complies with any of the clauses 40-90 and the methodcomprises moving said at least one part carried by the hoisting systemalong said support arms with the driving system.

Clause 177. Method according to any of the clauses 91-176, wherein theprovided vessel complies with any of the clauses 40-90 and the methodcomprises moving said at least one part carried by the hoisting systemalong the rails.

Clause 178. Method according to any of the clauses 91-177, wherein theprovided vessel complies with any of the clauses 40-90 and the methodcomprises moving the hoist members along the support arms with thedriving system while carrying the said at least one part.

Clause 179. Method according to any of the clauses 91-178, wherein theprovided vessel complies with any of the clauses 40-90 and the methodcomprises placing said at least one part carried by the hoisting systemon the deck of the vessel.

Clause 180. Method according to any of the clauses 91-179, wherein themethod comprises transferring said at least one part from the vesselonto a quay by positioning the second hull side adjacent to the quay andmoving said at least one part from the vessel to the quay while movingover the second hull side.

Clause 181. Method according to any of the clauses 91-180, wherein themethod comprises transferring said at least one part from a quay ontothe vessel by positioning the second hull side adjacent to the quay andmoving said at least one part from the quay to the vessel while movingover the second hull side.

Clause 182. Method according to any of the clauses 91-182, wherein saidat least one part is the support structure.

Clause 183. Method according to any of the clauses 91-182, wherein saidat least one part is the top side.

Clause 184. Method according to any of the clauses 91-183, wherein themethod comprises removing the support structure while the vessel carriesthe top side.

Clause 185. Method according to any of the clauses 91-184, wherein themethod comprises removing the support structure while the vessel carriesa further support structure.

Clause 186. Method according to any of the clauses 91-185, wherein themethod comprises removing the top side while the vessel carries afurther top side.

Clause 187. Method according to any of the clauses 91-186, wherein themethod comprises installing the support structure while the vesselcarries the top side.

Clause 188. Method according to any of the clauses 91-187, wherein themethod comprises installing the support structure while the vesselcarries a further support structure.

Clause 189. Method according to any of the clauses 91-188, wherein themethod comprises installing the top side while the vessel carries afurther top side.

Clause 190. Use of a vessel according to any of the clauses 1-90.

It will be apparent to those skilled in the art that variousmodifications can be made to the vessel and method according to theinvention without departing from the scope as defined in the claims.

1. A vessel for removal and/or installation of at least one part of asea platform comprising a support structure and a top side, said vesselcomprising a hull and two support arms located at a distance from eachother and attached to the hull, wherein the support arms in use extendbeyond the hull in a substantially horizontal direction.
 2. The vesselaccording to claim 1, wherein the support arms are located above thewater surface when carrying said at least one part of the sea platform.3. The vessel according to claim 1, wherein support units are attachedto the support arms and/or to the hull, and the support units comprise afirst coupling member.
 4. The vessel according to claim 1, wherein thesupport arms are movable relative to the hull.
 5. A method for removingat least a part of a sea platform comprising a support structure and atop side, which method comprises: providing a vessel according to claim1; positioning the support arms under the top side such that the supportstructure is located between the support arms; raising the support armsrelative to the water surface to fully support the top side with thesupport arms; continuing the raising of the support arms to move the topside at a distance from the support structure; and moving the vesselaway from the support structure in a substantially horizontal directionwhile fully supporting the top side with the support arms.
 6. The methodaccording to claim 5, wherein the support arms are movable relative tothe hull; and wherein the method comprises moving the support armsrelative to the hull before the support arms support the top side. 7.The method according to claim 5, wherein support units are attached tothe support arms and/or to the hull; wherein the support units comprisea first coupling member; and wherein the method comprises: attachingcooperating second coupling members to the top side; and raising thesupport arms relative to the water surface to couple the first couplingmembers with the second coupling members.
 8. The method according toclaim 5, wherein support units are attached to the support arms and/orto the hull; wherein the support units comprise a first coupling member;wherein the support arms are movable relative to the hull; and whereinthe method comprises: moving the support arms relative to the hull tocouple the first coupling members with the second coupling members. 9.The method according to claim 5, wherein the method comprises:positioning the vessel such that the support arms supporting the topside are positioned above a quay; and transferring the top side onto thequay.
 10. A method for installing at least a part of a sea platformcomprising a support structure and a top side, which method comprises:providing a vessel according to claim 1, wherein the top side of the seaplatform is fully supported by the support arms, positioning the topside above the support structure such that the support structure islocated between the support arms; lowering the support arms relative tothe water surface to place the top side on the support structure;continuing the lowering of the support arms to fully transfer the weightof the top side to the support structure and to move the support arms ata distance from the top side; and moving the vessel away from thesupport structure in a substantially horizontal direction.
 11. Themethod according to claim 10, wherein the support arms are movablerelative to the hull; and wherein the method comprises: moving thesupport arms relative to the hull after the transfer of the weight ofthe top side to the support structure.
 12. The method according to claim10, wherein support units are attached to the support arms and/or to thehull; wherein the support units comprise a first coupling member; andwherein cooperating second coupling members are attached to the top sideand coupled to the first coupling members; and wherein the methodcomprises: lowering the support arms relative to the water surface todecouple the first coupling members from the second coupling members.13. The method according to claim 10, wherein the method comprises fullysupporting the top side with the support arms by positioning the vesselsuch that the support arms are positioned above a quay on which the topside is located and transferring the top side on to the support arms.14. The method according to claim 5, wherein the support arms aremovable relative to the hull; and wherein the method comprises: movingthe support arms to match the dimensions of the top side which in usewill be supported.
 15. The method according to claim 5, wherein themethod comprises installing the support structure while the vesselcarries the top side.